Carbon rod or stick and mechanism for making the same



(NoModeL) 0. P. BRUSH. CARBON ROD 0R STICK AND MECHANISM FOR MAKING'THE SAME.

No. 274,904; Patented Apr. 3, 1.883.

I WITESSES INVENTO'R I r Y ATTORNEYS N. PETERS. Pholvliflwnphk. Wilmington. 7.6.

UNITED STATES PATENT OFFICE."

CHARLES F. IBRUSH, OF CLEVELAND, OHIO.

CARBON ROD R STlCK AND MECHANISM FOR MAKING THE SAME.

SPECIFICATION forming part of Letters Patent No. 274,904, dated April 3, 1883.

Application filed June 4, 1881. (No model.)

To all whom it may concern Be it known that 1, CHARLES F. BRUSH, of Cleveland, in the county of Ouyahoga and State of Ohio, have invented certain new and useful Improvements in Carbon Rods or Sticks and Mechanisinfor Making the Same; and I do-hereby declare the following to be a full, clear, and exact description'ot' the invention, such as will enable others skilled in the art to which it pertains to make and use it, reference being bad to the accompanying drawings, which form part of this specification.

My invention relates to an improvement in carbon rods or sticks for electric lights and mechanism for making the improved carbon rods; and the invention consists in a carbon rod or stick formed with a molded or compressed pointed end.

It further consists in improved mechanism for making carbon rods or sticks, as will here inafter be described, and pointed out in the claims.

Theadvantagesofpointed carbonsoverthose not so shaped are obvious. The electric'light between a fresh pair .of carbons previously pointed assumes its normal condition almost immediately, while if the carbons have not been pointed the light is very unsatisfactory for several minutes during the time the ends of'the carbons are burning to a proper shape.

It has heretofore been customary to mold carbons with unpointed ends and point them afterward by grinding. This operation is expensive and tedious, owing to the hardness of the material.

I employ a set or gang of molds consisting of a pair of metal plates, one side of each having parallel grooves milled into it, the crosssection of. each groove being nearly half that of the carbon to be produced. These plates are fitted into ametal frame, hinged at three corners and secured at the fourth by means of a key. One of the plates, beingplaced with its grooved side upward, is surrounded by the frame, which projects a suitable distance above The space thus formed is filled with the pulverized carbon mixture. The latter belng spread uniformly over the lower plate, the upper plate is placed in the frame grooved side downward. The whole is then heated sulficiently to render the carbon mixture slightly plastic, and then'the plates are. pressed together with great force by hydraulic or other means, whereby the carbon mixture is pressed into smooth and uniform bars of a shape corresponding to the interior of the molds. Then the frame is removed by extracting the key at one cornerand opening the frame, and the plates are removed from the inclosed. carbons. The latter are allowed to cool and become hard between flat plates of stone or metal, whereby crookedness is prevented.

In the drawings, Figure 1 shows in crosssection my form of molds, consisting of plates A B and frames 0. Fig. 2 is a plan View of plate B. Fig. 3 is an end view of plate B, showing depressions b b. Fig. 4 is a plan view of frame 0, showing joints d 6f and key-fastening g. Fig. 5 illustrates the method of cooling and straightening the carbons by confining them between two fiat surfaces. Fig. 6 represents one of my improved carbon rods or sticks.

In Fig. 1, A B are the grooved plates I have referred to, shown in sectional elevation. O is the frame. surrounding the plates, which frame is shown in plan in Fig. 4. It will be noticed that when the plates A B are brought nearly together the grooves in them form cylindrical and nearly separate cavities. D D are lugs formed on the plates A B to facilitate handling them. V

Fig. 2 is a plaii view of the plate 13. It will be seen that the grooves in the plate are contracted at one end, forming, when the other plate is applied, hollow truncated cones a a, which, when filled with the carbon mixture, form the pointed ends of the carbon rods; but the contraction of the grooves at one ezn d of the plate B would leave triangular flat places on the face of the plate. Now, when the plates are pressed together, the carbon mixture between the opposed flat portions of the two plates, having no escape except by flowing laterally, which it is very ,slow to do, especially when the plates are near together,-would greatly resist the pressure and relieve other portions of the molds from their due amount. I overcome this difficulty by hollowing outthe fiat spaces 1), as shown in Fig. 3, to a sufficient extent to accommodate, when under pressure, that portion of the carbon mixture lying between the triangular parts of the plates, so as to prevent at both ends, if desired, and in this case two sets of carbons might be molded at once by suitably increasing the length of the molds and afterward cutting the long rods in two.

Fig. 4 shows the frame 0 jointed at the corners d e f, and finally secured at the corner 9 by a key, as shown, one side of the frame, through which the key is inserted, being reduced in size and passing through the adjoining side of the frame. Thejoints d andf may be suppressed and these parts made rigid, if desired, the joint 6 being often sufficient. When a set or sheet of carbons is removed from the molds in a warm and somewhat'plastic condition and placed on a cold surface to cool and harden, that portion of the carbons touching the cool surface hardens and contracts while the remainder is still soft. Now,

when theremaining portions contract, although the amount of contraction is very small, it is often sufficient'to raise the ends of the carbons, and thus render them crooked. I overcome this difficulty by placin g another flat plate of metal or stone on the top of the carbons, as shown in Fig. 5, whereby they are simultaneously cooled on opposite sides. Th'eupper plate also acts by its weight to prevent crookedness.

Aftera set of carbons has cooled and become rigid'the thin web joining the different members is broken and the carbons are ready to be trimmed, if necessary, and baked.

What I claim is 1. As a new article of manufacture, a carbonstick or rod having a compressed pointed end, substantially as set forth.

2. Molds for forming electric-light carbons, provided with depressions b 12, substantially as and for the purpose specified.

3. The frame 0, provided with one or more hinged corners and akey-fastening, g, the key of said fastening being wed ge-shaped, substantially as set forth.

4:. Molds for forming electric-light carbons, provided with grooves having contracted ends a a, in combination with depressions b b, substantially as and for the purposes set forth.

5. Molds for forming electric-light carbons, consisting of platesAB, provided with grooves, in combination with a jointed frame, (3, substantially as and for the purposes specified.

6. Molds for forming electric-light carbons, consisting of p'latesA B, provided with grooves having contracted ends a a, in combination with ajointed frame, 0, substantially as and for the purposes set forth.

7 Molds for forming electric-light carbons, consisting of grooved plates A B, in combination with a jointed frame, 0, having a keyfa'stening, g, the key of said fastening being wedge-shaped, substantially as set forth.

In testimony whereofI have signed myname to this specification in the presence of two subscribing witnesses.

CHARLES F. BRUSH.

Witnesses:

J NO. GRoW1LL,Jr., ALBERT E. LYNCH. 

